How to fool a laptop into thinking a monitor is connected? - eviltoast

Hello! I converted an old laptop with a broken screen into a home server, and it all works well except for one thing: when I reboot it (via ssh), if no screen is connected, it will get stuck and refuse to boot. as soon as I connect an HDMI monitor, the fans will start spinning and it will start booting as usual. Then I can remove the HDMI and it will work flawlessly. I don’t know if this is a linux problem, a GRUB problem, or a firmware problem.
Any idea on how to solve this, or on how to fool it into thinking a screen is connected? The problem is not the lid switch as I removed the magnet from the screen, so it thinks the lid is always open

Thanks in advance!

  • Is it getting stuck in the BIOS? If you can’t ssh in, can you even ping it? Network should come up before graphics.

    Have you disabled the display manager?

    As someone eles mentioned, boot it with a screen and check the BIOS. Since this was a laptop, the BIOS is certainly expecting a display, so you might have to adjust something there.

    • tubbadu@lemmy.kde.socialOP
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      10 months ago

      Yes I can ping it!

      Have you disabled the display manager?

      yep, I did `systemctl set-default multi-user.target’

      As someone eles mentioned, boot it with a screen and check the BIOS. Since this was a laptop, the BIOS is certainly expecting a display, so you might have to adjust something there.

      I already looked into the bios but it was pretty empty, just a few options, nothing about displays or graphics card

      but now I have a doubts, perhaps there is a “show advanced settings” button somewhere that I didn’t see? I have to look for it

      • teawrecks@sopuli.xyz
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        10 months ago

        Most likely it’s hard coded in the firmware and not exposed as a BIOS option because the OEM didn’t ever think anyone would run into this. The dummy plug is your lowest effort workaround. Hope that works, good luck!

      • It could be Linux, too. Some distros have fancy boot graphics - look for something called “plasma” - not the KDE one, but a different one - and uninstall or disable that. It’s a common thing that hides the boot log behind a logo-and-progress bar. Arch doesn’t use it, so I haven’t seen it in years, but IIRC it can cause problems on headless systems.